An ex-vivo study on needle placement accuracy of a pre-clinical robotic guidance system

We analyze robot-guided needle placement accuracy of a pre-clinical system. The analysis will be performed with respect to angle, tip position, and holder position deviation between planned needle path and achieved needle position of the robot guidance system. To eliminate needle bending and forces towards the shaft, the analysis is performed by comparing the planned position with reached needle positions in air and a gelatin phantom. For the analysis we used a pre-clinical robot guidance system consisting of a joint-arm robot with 7 axes steered by a planning and guidance software featuring image segmentation and registration, virtual needle placement and ablation simulation. The system was used with an angiographic unit for robot calibration, trajectory planning and needle detection. For puncture, we used a 15cm 16G needle. We used n = 13 target positions and compared planned and reached needle path in air and a gelatin phantom. Study results are shown in the Table. Overall angular precision is below 1°, target precision below 4mm for a 15cm needle. Reproducibility of the needle path was far better than overall system precision leaving potential for further system improvements. The tip deviation is due to the current setup that controls the shaft position instead of the needle tip. Time required for robot motion to target, needle insertion, 3D scan, needle removal, and robot motion to rest position was less than two minutes for this technical setup. The analyzed system has a better angle and shaft precision as reported for comparative systems in the literature. It is easy to use and fast. The system has potential to serve as a fully integrated biopsy and therapeutic needle intervention system in head and neck, pulmonary and abdominal areas.Tabled 1Angular Deviation (degrees)Shaft Deviation (mm)Tip Deviation (mm)Air0.98±0.051.58±0.123.71±0.10Gelatin0.92±0.061.23±0.113.38±0.13Reproducibility0.36±0.041.03±0.120.99±0.09 Open table in a new tab